I will have some time most likely the week of Nov6 (off for a week of C++ Committee 'fun') to test different message size alternatives. I'll follow up with my results here for consideration the next time we are inclined to break the ABI compatibility :)
On Sunday, October 16, 2016, Brian Knox <bk...@digitalocean.com> wrote: > A new stable version would definitely help me in my quest to get ZeroMQ > support enabled by default in rsyslog in distros. > > On Sun, Oct 16, 2016 at 2:40 PM Doron Somech <somdo...@gmail.com> wrote: > >> I say lets bump. >> >> On Oct 15, 2016 20:32, "Luca Boccassi" <luca.bocca...@gmail.com> wrote: >> >>> As Thomas said, false sharing would be a real issue with 96. >>> >>> So given a release is long due, at this point I'd say to drop this for >>> the moment. >>> >>> What do we do for the change to union for zmq_msg_t? Bump ABI version or >>> not? >>> >>> On Thu, 2016-10-06 at 09:53 +0300, Doron Somech wrote: >>> > No new socket type, I worked at the time on binary message type, might >>> > complete it sometime, but it is not urgent. >>> > >>> > If there is a lot of performance penalty we can give it up, I will >>> > find another solution for the Radio-Dish. >>> > >>> > What about 96 bytes? same penalty? >>> > >>> > Regarding the binding, I'm not sure. >>> > >>> > On Sat, Oct 1, 2016 at 9:14 PM, Luca Boccassi <luca.bocca...@gmail.com> >>> wrote: >>> > > On Tue, 2016-09-27 at 09:41 +0300, Doron Somech wrote: >>> > >> Sorry for the late response, increasing the msg_t structure will be >>> > >> great, however this will require changing a lot of binding. >>> > > >>> > > I think I remember we need it for the new socket types, is that >>> correct? >>> > > >>> > > There is a large performance penalty (intuitively due to not fitting >>> > > into a single cache line anymore, but haven't ran perf/cachegrind), >>> and >>> > > the throughput with vsm type messages goes down by 4% (min) and 20% >>> > > (max) for TCP, and 36% (min) 38 (max) for inproc, which is quite a >>> lot, >>> > > so we need to be sure it's worth it. >>> > > >>> > > Regarding the bindings, after a quick search on the Github org, I >>> could >>> > > only see: >>> > > >>> > > https://github.com/zeromq/lzmq/blob/master/src/lua/lzmq/ >>> ffi/api.lua#L144 >>> > > https://github.com/zeromq/clrzmq4/blob/master/lib/zmq.cs#L28 >>> > > https://github.com/zeromq/pyczmq/blob/master/pyczmq/zmq.py#L177 >>> > > >>> > > Other bindings just import zmq.h. Did I miss any? >>> > > >>> > >> Sorry for disappearing, baby and full time job is a lot :-), >>> hopefully >>> > >> I'm back... >>> > > >>> > > No worries, perfectly understandable :-) >>> > > >>> > >> On Mon, Aug 29, 2016 at 6:46 PM, Luca Boccassi < >>> luca.bocca...@gmail.com> wrote: >>> > >> > Sorry, I meant if we go with (1), not (2), we might bump the size >>> as >>> > >> > well, since we are already doing another ABI-breaking change. >>> > >> > >>> > >> > I agree on the solution as well. >>> > >> > >>> > >> > On Mon, 2016-08-29 at 17:12 +0200, Pieter Hintjens wrote: >>> > >> >> I'm confused between the (1) and (2) choices, and can't see where >>> > >> >> bumping the message size fits. >>> > >> >> >>> > >> >> Nonetheless, I think bumping the size, fixing the alignment >>> issues, >>> > >> >> and bumping the ABI version is the best solution here. >>> > >> >> >>> > >> >> On Fri, Aug 26, 2016 at 12:33 PM, Luca Boccassi < >>> luca.bocca...@gmail.com> wrote: >>> > >> >> > I've given some more thoughts and testing to the alignment >>> issue. I can >>> > >> >> > reproduce the problem by enabling alignment checks on x86 too. >>> > >> >> > >>> > >> >> > But most importantly, I think we cannot get away from bumping >>> the ABI >>> > >> >> > with this fix, however we rearrange it, simply because >>> applications need >>> > >> >> > to be rebuilt against the new header to be fixed. A simple >>> rebuild of >>> > >> >> > the libzmq.so is not enough. And the way to do this is to bump >>> the ABI >>> > >> >> > so that distros can schedule transitions and rebuilds and so >>> on. >>> > >> >> > >>> > >> >> > So the choice list is now restricted to: >>> > >> >> > >>> > >> >> > 1) Bump ABI >>> > >> >> > 2) Revert the fix and leave everything broken on sparc64 and >>> some >>> > >> >> > aarch64 (rpi3 seems not to be affected, must depend on the SoC >>> flavour) >>> > >> >> > >>> > >> >> > If we go with 2, we might as well get 2 birds with one stone >>> and bump >>> > >> >> > the zmq_msg_t size to 128 as we have talked about in the past. >>> > >> >> > >>> > >> >> > Doron, this would help with the new UDP based socket types >>> right? >>> > >> >> > >>> > >> >> > Pros of bumping msg size: >>> > >> >> > >>> > >> >> > - we can get rid of the malloc() in the lmsg type case as all >>> the data >>> > >> >> > will fit >>> > >> >> > >>> > >> >> > Cons: >>> > >> >> > >>> > >> >> > - for the vsm/cmsg type cases (for most architectures anyway) >>> it won't >>> > >> >> > fit anymore into a single cacheline >>> > >> >> > >>> > >> >> > Given all this, I'd say we should go for it. >>> > >> >> > >>> > >> >> > Opinions? >>> > >> >> > >>> > >> >> > On Sat, 2016-08-13 at 16:59 +0100, Luca Boccassi wrote: >>> > >> >> >> Hello, >>> > >> >> >> >>> > >> >> >> Trying to give some thoughts again on the libzmq 4.2 release. >>> It's >>> > >> >> >> really long overdue! >>> > >> >> >> >>> > >> >> >> The main issue from my point of view is this change: >>> > >> >> >> >>> > >> >> >> https://github.com/zeromq/libzmq/commit/ >>> d9fb1d36ff2008966af538f722a1f4ab158dbf64 >>> > >> >> >> >>> > >> >> >> -typedef struct zmq_msg_t {unsigned char _ [64];} zmq_msg_t; >>> > >> >> >> +/* union here ensures correct alignment on architectures >>> that require >>> > >> >> >> it, e.g. >>> > >> >> >> + * SPARC >>> > >> >> >> + */ >>> > >> >> >> +typedef union zmq_msg_t {unsigned char _ [64]; void *p; } >>> zmq_msg_t; >>> > >> >> >> >>> > >> >> >> >>> > >> >> >> This is flagged by the common ABI checkers tools as an ABI >>> breakage >>> > >> >> >> (see: http://abi-laboratory.pro/tracker/timeline/zeromq/ ). >>> And it makes >>> > >> >> >> sense from this point of view: if some applications on some >>> > >> >> >> architectures are broken due to wrong alignment, they would >>> need to be >>> > >> >> >> rebuilt, and the way to ensure that is to bump the ABI >>> "current" digit >>> > >> >> >> to make sure maintainers do a rebuild. >>> > >> >> >> >>> > >> >> >> On the other hand, signaling an ABI breakage is a pain, and a >>> cause of >>> > >> >> >> major churn for packagers and maintainers. It means for >>> example a new >>> > >> >> >> package has to be created (eg: libzmq5 -> libzmq6), and a >>> transition has >>> > >> >> >> to be started and all reverse dependencies need to be >>> rebuilt. And if >>> > >> >> >> this is pointless for all save a few corner cases (eg SPARC64 >>> as for >>> > >> >> >> above) it's all quite frustrating. >>> > >> >> >> >>> > >> >> >> So we have a choice to make before we release 4.2, four >>> possibilities as >>> > >> >> >> far as I can see: >>> > >> >> >> >>> > >> >> >> 1) Ignore the ABI checkers and get yelled at by maintainers >>> and >>> > >> >> >> packagers. Also the SPARC64 users will most likely NOT get >>> their bug >>> > >> >> >> fixed >>> > >> >> >> 2) Bump ABI revision to 6 and get yelled at by maintainers >>> and packagers >>> > >> >> >> 3) Revert the above change and postpone it to when we have a >>> more >>> > >> >> >> generally useful reason to break ABI (bump zmq_msg_t from 64 >>> to 128 >>> > >> >> >> bytes for example, Doron?) >>> > >> >> >> 4) Try to be clever and revert the above change and use >>> something like >>> > >> >> >> #pragma pack(8). This will fool the ABI checkers (I tried >>> it), and given >>> > >> >> >> that typedef is only used externally to allocate the right >>> size it >>> > >> >> >> shouldn't actually affect anything, apart from the users of >>> SPARC64 >>> > >> >> >> which should get the bugfix with this too. This is very >>> sneaky :-) >>> > >> >> >> >>> > >> >> >> CC'ing Lazslo, the Debian maintainer, given what we choose to >>> do might >>> > >> >> >> result in a lot of work for him :-) >>> > >> >> >> >>> > >> >> >> Opinions? >>> > >> >> >> >>> > >> >> >> Kind regards, >>> > >> >> >> Luca Boccassi >>> > >> >> >> >>> > >> >> >> On Tue, 2016-05-03 at 10:39 +0200, Pieter Hintjens wrote: >>> > >> >> >> > Hi all, >>> > >> >> >> > >>> > >> >> >> > I'm just throwing some ideas on the table. We have a good >>> package of >>> > >> >> >> > work on master and it's probably time to make a 4.2 release. >>> > >> >> >> > >>> > >> >> >> > Luca has already back-ported the enable/disable draft >>> design from >>> > >> >> >> > zproject (CZMQ et al). Yay! So we can now release stable >>> master >>> > >> >> >> > safely, while continuing to refine and extend the draft API >>> sections. >>> > >> >> >> > >>> > >> >> >> > I propose: >>> > >> >> >> > >>> > >> >> >> > - to end with the stable fork policy; this was needed years >>> ago when >>> > >> >> >> > we had massively unstable masters. It's no longer a problem. >>> > >> >> >> > - to use the github release function for libzmq releases >>> and deprecate >>> > >> >> >> > the separate delivery of tarballs. >>> > >> >> >> > - we aim to make a 4.2.0 rc asap, then fix any issues we >>> get, with >>> > >> >> >> > patch releases as usual. >>> > >> >> >> > - we backport the release function to older maintained >>> releases (4.1, >>> > >> >> >> > 3.2) so that their tarballs are provided by github instead >>> of >>> > >> >> >> > downloads.zeromq.org. >>> > >> >> >> > >>> > >> >> >> > Problems: >>> > >> >> >> > >>> > >> >> >> > - this will break a few things that depend on >>> downloads.zeromq.org. To >>> > >> >> >> > be fixed as we go. >>> > >> >> >> > - github tarballs are not identical to source tarballs, >>> particularly >>> > >> >> >> > they lack `configure`. I propose changing our autotools >>> build >>> > >> >> >> > instructions so they always start with `./autogen,sh` no >>> matter where >>> > >> >> >> > the sources come from. >>> > >> >> >> > >>> > >> >> >> > I think this will work and also let us gracefully >>> deprecate/switch off >>> > >> >> >> > the downloads box. >>> > >> >> >> > >>> > >> >> >> > -Pieter >>> > >> >> >> > _______________________________________________ >>> > >> >> >> > zeromq-dev mailing list >>> > >> >> >> > zeromq-dev@lists.zeromq.org >>> > >> >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev >>> > >> >> >> >>> > >> >> >> >>> > >> >> > >>> > >> >> > >>> > >> >> > >>> > >> >> > _______________________________________________ >>> > >> >> > zeromq-dev mailing list >>> > >> >> > zeromq-dev@lists.zeromq.org >>> > >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev >>> > >> >> _______________________________________________ >>> > >> >> zeromq-dev mailing list >>> > >> >> zeromq-dev@lists.zeromq.org >>> > >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev >>> > >> > >>> > >> > >>> > > >>> >>> _______________________________________________ >> zeromq-dev mailing list >> zeromq-dev@lists.zeromq.org >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev > >
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